Oil burner and control therefor



Nov; 19, 1929.

' GQD. SUNDSTRAND QIL BURNER AND CONTROL THEREFOR OI iginal Filed April 14. 1924 4 Sheets-Shet 1 cimaf Davad sundfimfld Nov. 19, 1929. e. D. SUNDSTRAND 1,736,420

OIL BURNER AND CONTROL THEREFOR Original Filed April 14, 1924 4 Sheets-Sheet 2 0/1. SUPPLY PIPE Nov. 19, 1929.

G. D. SUNDSTRAND OIL BURNER AND CONTROL THEREFOR Original Filed April 14. 1924 4 Sheets-Sheet 4- 171067115% G'zmtaf David undafmnd,

Patented Nov. 19, v 1929 ITE STATES PATENTY OFFICE;

GUSTAF DAVID SUNDS'IRAND, OF ROCKFORD, ILLINOIS, ASSIGNOR, BY MESNE ASSIGIF- MEN'I'S, TO SUNDSTRAND ENGINEERIN CORPORATION ILLINOIS G COMPANY, OF ROCKFORD, ILLINOIS, A,

OIL BURNER AND CONTROL THEREFOR -App1ication filed April 14, 1924, Serial No. 706,240. Renewed May 22, 1929.

This invention has reference to a control for oil burners and more particularly to burners of the house-heating type.

Such burners ordinarily include oil-feeding means and air feeding means electrically driven, and an automatically functioning regulator or control device to set the oilfe'eding means and the air-feeding means into operation according to conditions in the building or apartment to be heated. It is the object of the present invention to provide an improved system for such a burner which will automatically start and stop the device according to the room conditions and likewise according to the boiler conditions.

It is a particular object of the invention to provide reliable means operable to initiate combustion by adjustment or operation of the various parts in a predetermined sequence.

It is another object of the invention to provide a plurality of safety devices electrically associated for mutual co-operation to control the burner automatically by a change in both normal and abnormal conditions of the room or heater.

Another object of the invention is the provision of a novel ignition system employing a gas flame, electrically ignited, as the direct igniting means for the oil.

Still another object of the invention is the employment of a repeating mechanism adapted to cause a continued repetition of the'starting operation in case of a failure thereof to ignite the oil, or upon extinguishing of the flame.

Still another object is the provision of improved means operated by the accumulated fuel to prevent operation of the device after numerousattempts at ignition caused by the operation of the repeating device.

A still further object of the invention is the provision of electrical circuits and of a construction adapted for the use of mercury switches to eliminate any danger which might arise from sparking at other types of switches.

Still other and ancillary objects and advantages will be apparent from the following description relating to one particular embodiment and application of my device.

The control proper is adaptable for use with various types of oil burners by making suitable and simple changes in the mechanical parts thereof. Furthermore, it is possible completely to separate the circuit of the electrical safety devices fromthe remaining part of the device, but this is usually not the preferable embodiment of the invention.

For the purpose of description and explanation I have chosen to illustrate in the drawings the invention as I have adapted and applied it to a type of oil-burning apparatus disclosed in my co-pending application Serial No. 575,642, filing date July 17, 1922. However, it is to be understood that this is by no means a limitation of the invention to such application, is will hereinafter be more apparent by the statement of the invention'in the appended claims.

In the drawings: Figure 1 represents a steam boiler equipped with an oil burner comprising my control.

Fig. 2 is a front elevation of the oil drip switch for stopping the burner.

Fig. 3 is a vertical mid-section of the switch shown in Fig. 2.

Fig. 3 shows a combustion bowl which serves to collect unconsumed oil.

Fig. 4 is a front elevation of the controlling mechanism.

Fig. 5 is a plan view of the controlling mechanism from the plane of the line 5-5 in Fig.

Fig. 6 is a diagrammatic view of the electric circuits of the control showing a low voltage circuit for the electrical safety switches.

Fig. 7 is a diagrammatic view of the electrical circuits for the control in which the safety devices are in circuit with the main In the drawings the burner is shown arranged to heat a'steam boiler 10. The oil burning apparatus supplies air, oil, gas for ignitionof the oil and electricity for operating the apparatus and for igniting the gas.

The means for supplying these are associated into a unit supported on a box-like base 7 11 having a removable front plate 12. The controlling mechanismis situated within this base. Mounted on the base is an electric motor 14 alined with an air blower 15 and connected to a suitable oil pump (not herein shown). likewise axially mounted with the motor and the blower. Electric current is suitably supplied through a main switch 16. The air from the blower 15 is conducted through a'large conduit 17 into the combustion space. Within the combustion space the air conduit 17 communicates with a suitable combustion bowl as 17*. A mixture of oil and air produced by the motor-driven mechanism'is supplied through a'conduit 18 to. a

suitable'nozzle19 (Fig. 9) within the combustion space. The conduit passes through i an opening (Fig. 9) ma plate 20 secured to the door 21 of the boiler. Also secured to the plate 20 is a casing 22 for the ignition means. A tube 23 leads from a suitable gas supply to the control box. A gas tube 24 and an elec- 'tricconduit 25 extend from thecontrol box tothe casing 22. Portions of the conduits 18,-24 and 25 are of flexible construction so that the door 21 may be swung partially open when desired.

In the present embodiment of the invention, means is provided for heating an electrical resistance to incandescence, and then passing a stream of gas over the element to ignite the gas. The gas flame is projected into "the path of the spray of oil and air discharged from the nozzle 19 toignite the oil, and air is supplied through theconduit 17 to continue the combustion, whereupon both the heating element and the gas are shut off. Theseoperations are performed in proper sequence by a controlling mechanism located in the box 11. Figs. 3 and 4 illustrate a particular embodiment of this mechanism' in which rotary cams efi'ect the sequential operation either through mechanical connections or through the operation of electrical switches. v V

The controlling mechanism comprises generally a rotary structure in the form of a shaft having a plurality of cams thereon, one revolution of the shaft producing the starting and the stopping operations of the apparatusl The cams move certain arms one of which is-adapted to cause the .motion of the cams to be arrested in either of two posi- *tions,\hereinafter referred to as the idle position and the operating position, such terms referring to the desired state of operation. of the oil-burning apparatus. The mechanism generally is mounted in the box 11 by securing its base 30 therein. The rotary shaft 31 has rigid thereon a plurality of cams 32, 33, 34, 35 and 36 and a gear 37. Means is provided to rotate the shaft comprising a small control motor 38 having a Worm gear 39 on its shaft, suitably connected to the gear 37 through a reducing gear train 40 4142'43. An electrical connection board 44 is mounted on the base for simplifying the electrical connections to the various parts of the control. From this board a pair of wires 45 lead to the control motor.

Un a shaft46 are mounted a plurality of arms which engage the corresponding cams. Each arm is suitably shaped for its distinctive operation, but each has a generally similar construction in certain respects. For example, each arm is individually demountable from the shaft 46 without regard to the others, whereby removal for inspection or repair is facilitated. Each arm is mounted for assuming slightly angular positions on each side of the horizontal as illustrated by the two arms visiblein Fig. 4. Each arm is provided with a roller 47 which rides on its cam. Arm 48 is shown, with its roller in the depression of the cam, and arm 49 is shown with its roller on the raised portion of its cam;

A short downwardly directed projection 50 is shown on arm 48 substantially at the pivotal center thereof, and a tension spring 51 is attached thereto and to a stud 52. A slot in the arm directed angularly toward the spring provides at its circular bottom portion the plvotal bearing of the arm on the shaft 46, r

the arm being held immovable longitudinally of the shaft by a peripheral groove 53 therein.

The arm 48 is provided with an extension to the right in Fig. 4 which is connected through a link 54 to a valve 55 in the oil sup-= ply pipe 55 leading tothe intake side of the oil pump hereinbefore alluded to. The projection 50 above described is made longer than in the other cases to provide sufficient strength to operate the valve when the roller 47 rides into the depression ofits cam 36.

The arm 49 has a similar extension to which a rod (not shown) may be attached to trip it manually independently of the cam 35. The arm 49 lies in a depression of its cam when the control is in both idle and operating positions. This is a necessary inci dent of the arrangement herein disclosed, since this arm 49 carries a mercury switch 56 provided with terminals 57, hereinafter called contact C, at-the right end (Fig. 4) thereof. By this construction the contact is closed only when the roller on arm 49 rides on the elevations of its cam. This switch 56 is located on the circuit of the control motor 38 andis so disposed in the normal operation of the device that when the cams reach either the idle or the operating position, the circuit to the control motor is broken and the motion of the cams is arrested. The manual operation of the switch minals 60 in the right end, hereinafter re-- 56, independently of its ca1n,'will set the control in operation for the purpose of testing or inspection without the necessity of disturbing the more delicate controls in the electrical control circuit.

The arm 58 which is operated by the cam 34, carries a mercury switch 59 having terferred to as contact A, and terminals 61 in the left end, hereinafter referred to as contact B. This switch istilted in one direction at the idle position of the cams and in the other direction at theoperating position of the cams, functioning as a shifting means for It is arranged in the electrical circuits to permit starting of the control motor 38 by means other than through the above described switch 56.

The arm 62, which is operated by the cam 33, does not carry a switch, but is provided with a curved finger 63 (Fig. 4) which is pushed by the cam to open a spring-pressed gas valve 64 in the gas supply line 23. This arm causes a flow of gas for a short period of time, depending upon the speed of the cams'and the form of the cam 33.

The arm 66, which is operated by the cam 32, carries a mercury switch 67 having terminals 68, hereinafter called contact D, which are arranged in the circuit to the main motor 14, the cam 32. causing said circuit to be closed in the operating position of the cams.

Other arms, switches, and cams may be added as required. The addition of another cam and switch is desired in one particular application of my invention which is herein disclosed. This instance has reference to that form of the invention wherein the electrical control circuit is made independent of the circuits in the controlling mechanism, as will appear hereinafter. In Figs. 4 and 5 I have shown an ignition transformer having a primary coil 70 mounted on the control base 30. The primary terminals 71 are connected to the board 44. The secondary coil 72 of this transformer is alow-voltage heavy current carrying coil connected to an ignition element within the combustion space by the conductors 73 in the conduit 25. It may be desired to close the primary circuit of the'transformer by an independent switch so that it operates on passing from the idle to the operating position of the cams, during which interval ignition occurs. This is shown in Fig. 6 using cam 35 of Fig. 8. 7 However, it is preferably connected in parallel with the control motor 38 and is operated by the same mercury switch 56 by closure of contact G, as shown in Fig. 7.

In the practical use of an oil burner it is started and stopped a number of times in every twenty-four hours. The success of such a burner is consequently greatly dependent" upon the reliability of the ignition means.

have provided an ignition system which is practically isolated from the flame and hence not subject to disintegration or other deleterious efi'ects arising from intense heat. In Figs. 9 and 10 the space at the right of the door 21 is within the furnace or combustion space. Beneath the combustible mixture pipe 18 there passes through the door a casing 74, of tubular form provided on the inside of the furnace with a projecting spout or nozzle 75 opening into the furnace chamber and directed toward the jet of combustible mixture discharged from the nozzle 19. A gas flame issuing from, the nozzle 75 ignites the comcertain control circuits hereinafter described.

Bolts 82 hold the bars together and insulation I 83 spaces and insulates them. One of the bars 79 is mounted on a fixed plate 84 by a similar arrangement of bolts 85, and insulation 86. The ignition element 77 is suitably connected to the bus bars 79 and 80.

In the operation of the above described ignition device, the casing 74 provides an ignition chamber containing ,the ignition element 77 and the gas orifice 7 6. Ignition takes place in the chamber thereby exhausting the oxygen therein, whereupon burning of the gas takes place from the tip of the spout 75. It is clear that in the operation of the oil burner, the ignition element 77 is substantially removed from flames of both gas and oil at all times except atthe initial ignition of the as. g Means is provided for shutting off the Whole apparatus by an accumulation of un- I consumed oil. While such. means generally slightly inclined for this purpose. A pipe 87 is connected to the'air conduit to receive the draining oil. The pipe is provided with an elbow 88 having a horizontally disposed axial nip le 89 upon which is mounted a rotatable follow drum 90. Unconsumed oil' may flow from the furnace into the drum through the above described connections.

assigned above.

The drum is provided with a normally vertical transverse partition 91 which passes to one side of the axial nipple 89, thereby permitting accumulation of oil in but one portion of the bottom of the drum. This unbalances the drum and tilts it on its axis. Mounted on the face of the drum is a casing 92 within which is disposed a mercury switch 93 having a contact at each end as G and H with three wires 94, 95 and 96 leading thereto. The contact G is normally closed when the drum is empty and the contact H becomes closed when the drum tilts. A pouring spout 97 is provided for thepurpose of draining the oil from the drum by manually tilting it for that purpose.

In Fig. 1 there is shown in the boiler flue 10* a thermostatic element 98 which is. affected by the heattherein to move a mercury switch 99 to open its contact K. .The

function of this device is to cause repetition of the ignition operation in case of failure thereof or in case of extinguishment of the flames. The operation will be more specifically described hereinafter.

The sequence of operations, mechanically and electrically produced by the control'm'echanism above described, is diagrammatically represented by Fig. 8. This is arranged for consideration in connection with Figs. 6 and 7 which represent diagrammatically the electrical circuits of the control; diagram (Fig. 8) the numbered lines represent the corresponding cams after being rectified as to the cam surface. The rectification is indicated by'the division of the cir cumference into 360, these divisions being indicated in quadrant periods. l/Vith reference to cams 32, 35, 35 and 36 in Fig. 8, the shaded block above the lines indicates the elevations of the cam and likewise, in each case, the closure of the oil valve or switch contacts operated'thereby'. With reference to cams 33 and 34, the shaded block below the line indicates the closure of the gas valve and contact B, respectively, when the roller lies in the depression of the cam. In the electrical diagrams those mercury switches which are operated by the cams have contacts bearing designations by letter, already In the cam diagram the same letter is placed in the shaded area to indicate directly that said contact is closed. In the case of the gas and oil valves the word itself is inserted.

The complete operation of the device under normal conditions will be clear from the following description of Fig. 7. For the purpose of simplifying the explanation a portion of Fig. 7 may be neglected so far as the normal operation is concerned. The

wires 100, 101 and 102 are three wires leading from connection board 44 (Fig. 4) to a room thermostat 103 having the cold-side contact E and the heat-side contact F.' By

In the cam' following the dotted lineslOl and 102, the

and 105. The main motor 14 is arranged to be connected in circuit across the power line through the mercury switch 67. The control motor 38 and the ignition transformer 70 are arranged to be connected mutually in parallel across the line, through the mercury switch 56. A variable resistance 106 may be employed in series with the control motor, as

a suitable means for adjusting its speed for proper operation. The wires 107 and 108 form a shunt circuit around the contact C and lead to the room thermostat 103 through the cam tube contacts B and A in a well known manner.,

Let us assume that the apparatus in the idle position, the contact A being closed, as

shown in Figs. 7 and 8. When the temperature in the room drops to the predetermined point, the room thermostat 103 closes the contact E, as shown in Fig.7, thus complet ing the circuit (shown in heavy lines) to the control motor 38 through the following elements 10%108102E100A107 thence through the motor38 and the ignition transformer 70 to the line 105. The cams are caused to rotate out of the idle position to, say, one quarter turn or in the diagram. The ignition element is heating up by with or after the closing of contact C so that there is no sparking atthe break in the thermostat cam tube at contact A. The contact B is closed simultaneously with the opening of A so that the device is ready for closure of the hot side of the room thermostat; The shaft 31 continues to rotate. Shortly after the quarter turn the. oil valve 55 is opened by the cam 36. At a half turn the gas valve 64 is opened and a circuit is closed through the main motor by cam 32 operatingv contact D. At 270, or about a three-quarter turn, the gas valve 64 is closed. In the meantime the gas had been immediately ignited by the resistance element and the mixture of oil and air had reached the nozzle 19 and had been ignited by the gas flame before the gas was shut ofl. The burner now being in normal operating condition, the contact C is opened by cam 35 and the control motor 38 and the ignition transformer are thereby cut out and the mechanism stopped with the cams resting in the operating position.

The contact B being closed by the shifting switch 59 the room thermostat must contact the hot side to again operate the control motor. When theroom is sufficiently heated 'contact'A has been opened, simultaneously the current is again established as before, but

passes through wire 101 and contact B rather stat.

Fig. 6 shows a modified form of electrical circuit in which the room thermostat circuit including wires 107 and 108 is placed in a low voltage line rather than in the high voltage line of Fig. 7. This is accomplished by the use of two transformers having primary coils 109 and 110 and low voltage secondary coils 111 and 112. The wires 107 and 108 are placed in circuit with the secondary coils 111 and 112 connected in series. One primary coil, as 109, is connected across the main lines 104 and 105 by the wires 113 and 114. The remaining primary coil 110 is connected to one side of the line, as 105, by the wire 115 and to the motor side of the contact C by the wire 116. By this arrangement the coil 111 becomes the power source for the room thermostat circuit and the coil 112 becomes the load, inducing a current in the local circuit .110116381051151 10. The connections are necessarily so made that the coil 110 and the line voltage become opposed 'to each other, when the contact C is closed, to

insure the proper operation of this arrangement. It will be observed that in Fig. 6- a separate cam tube contact 0 has been-provided for the ignition transformer and that a cam 35 is. indicated therefor in Fig. 8. This arrangement takes the ignition transformer from the circuit which is operated by the double transformer connection and thereby permits use of transformers havlng a lower capacity than the arrangement of Fig. 7 would require wherein the 1gn1t1 on transformer and the control motor are connected in parallel. a

In Fig. 6 the parts are. arranged 1n the operating position of. the 011 burner. This is indicated in the diagram by theheavy lines indicating current through the main motor 14. In this position the room thermostat must operate by closure of-its heat contact F for. which purpose the contact B is closed. -The room thermostat is indicated with the contact F still. open, since the machine is operating to raise the room temperature sufiiciently to close it. Whenth s point is reached the lowvoltage circuit 1s completed as follows 1111 1210894:*G j

96 M 102' F- -101-B 107 f 111. The current in this circuit induces a current in the local circuit 11011638105-115 110." The effect of this is to start the control motor 38 to bring the device from the operating to the idle position. Reference to Fig. 8 shows the sequence of operations. The control motor' is put across the line voltage by the cam 35 closing the contact C, the cam 34 opening the contact B simultaneously with or, after closing 0. The oil valve is shut by cam 36 and the main motor contact D broken by cam 32. The control motor rotates the cams sufficiently to accomplish these operations, whereupon the cam 35 opens the contact O and the device stops in the idle position heretofore described with reference to Fig. 7.

A plurality of protective or safety devices are provided for the purpose of rendering the operation of the oil burner practically au; tomatic in so far as it may be made to operate without human intervention.

From the above description it is apparent that the apparatus may be started or stopped by completing the circuit between wires 107 .and 108. .The effect of this has been generally described by considering the ordinary thermostat circuit having a heat side contact F and a cold side contact E (Fig. 7 The safety devices comprise a. plurality of additional withthe boiler for actuation by conditions therein, and effective to actuate the controlling mechanism exactly as conditions require. The ultimate effect is to close the circuit between wires 10? and 108 in each instance of operation.

First, means is provided to cause a repetition of the starting operation upon a failure to ignite. Said means is adapted to repeat the starting operation not only once, but

.indefinitely unt1l ignition takes place or intervention occurs. The flue thermostat 98 heretofore alluded to is adapted when cold to close the contact K thereby closing the heat circuit of the room thermostat by a shunt around the contact F. The thermostat 98 may be disposed anywhere near the combustion zone so as to be quickly heated upon initiation of fuelcombus'tion.

Herein it has been described as located in the smoke flue. Upon response to the heat of the flue gases the thermostatic contact K opens. As shown in Fig. 7 the closure of K simulates a heated room, and hence stops the machine. No sooner is it stopped than the switches operatively associated U j peating switch serves to recycle the starting mechanism on a failure in the power line whereby to produce ignition. It is a particular advantage of this recycling switch that it is notoperative upon a momentary interruption of the power, but only upon such an 1nterruption as is sufficient to extinguish the flame.

Secondly, I have provided the oil drip mechanism to limit recycling. The mercury switch 93 on the oil drip drum 90 has its contact G normally closed to complete the connection from wire 108 to wire 102 at the common point of the room thermostat by means of the following circuit, 10894G'96 M102. Upon breaking contact G the room thermostat i cut out of the electrical control circuit. It is possible for the thermostatcircuit to become broken while the main motor is running so that means must be provided to stop it. By using the contact H the immediate closure thereof short-circuits the leads s101'and 108 to the room heat contact F, by means of the wires 94, 95 and 117.

Thirdly, it is desirable that an excessive heat in the boiler or furnace 10 shall operate to stop the burner. This is accomplished in a well known manner by the use of a two point switch. In the steam boiler of Fig. 1, a pressure-controlled switch 118 has two con.- tacts L and M (Fig. 7). Normally, the contact M is closed and completes the circuit from wire 96 to the room thermostat. At a predetermined maximum boiler pressure the contact M is snapped open and the-contact L is closed. The opening of M cuts out the room thermostat so that it cannot operate to stop or start the burner. But the simultaneous closure of L short-circuits the leads to the 'heat circuit of the room thermostat by connecting wires 101 and 108 through the wires 117 .-l18contact Lwire 96 contact G'-wire 94. Upon a drop in the boiler pressure to a predetermined low point the switch 118 is again shifted to snap closed the contact M for further normal operation of the device- It will be understood that when the o1l burner is applied to a hot water heating plant, a switch similar to the switch 118, but sensitive to the temperature of the water would be used.

By so connecting these various safety devices.- each performs its functions atthe proper time and renders the burner idle or 'efiicient and desirable degree.

I claim as my invention:

1.. A fuel burner for delivering fuel to a combustion space, comprising, in combination, means for supplying a mixture of oil and air to said space, rneans for supplying combustion supporting air to said space, a motor to operate said two supplying means, a supply of ignition fuel, an electrical ignition device, a valve to control the burner fuel, a valve to control the ignition fuel, a switch to control said motor, a switch to control said ignition device, a controlling mechanism for starting and stoppingsaid burner automatically, a control motor for said mechanism, operatively effected by said ignition switch, a three-wire-two-circuit starting system for said control motor, shifting means to connect alternately one of said circuits across the,'

ignition switch whereby to start the control motor upon closing said circuit, a plurality of cams in said controlling mechanism adapted to operate said fuel valves and motor switch to start'and stop the burner, one of said cams operating said shifting means to connect the second controlling circuit across the ignition switch, another cam being adapt- 10o ed to operate the ignition switch to cut out the ignition device and to stop the control motor after a partial revolution of the cams, whereby the burner is left in operating condition, said ignition switch cam being likewise adapted to stop the control motor after a complete revolution of the cams, whereby the burner is left in idle position, the closure of the second controlling circuit starting said mechanism from the first stopped or operat- 1 ing position to the second stopped or idle po sition.

2. A fuel burner comprising, in combination, a heater, a heat absorbing medium therein to heat an apartment, a three-wire th'crmo- 1 5 stat'in said apartment, a motor for supplying combust on materlal to said heater, auto .matic ignition means to initiate combustion,

an .'automatic self-stopping controlling mechanism arranged to start and stop said 120 motor and ignition means, a starting circuit and a stopping circuit to said thermostat, means insaid co trolling mechanism for connecting said tw circuits alternately to said controlling mechanism to effect the starting '12s thereof by closure of the connectedcircuit, a two way snap switch arranged to open one contact and to close another contact by a pre-. determined maximum state in the heate rwhereby to short the stopping circuit to the thermostat, said two-way snap switch being further arranged to open said second contact and to close said first contact at a predetermined minimum state in the heater whereby to complete the circuits to the thermostat.

3. A. fuel burner comprising, in combination,'aheater, a heat absorbing medium therein to heat an apartment, a two-circuit thermostat in said apartment, a motor for supplying combustlon material to said heater,

automatic ignition means to initiate combustion, an automatic self-stopping controlling mechanism arranged to start and stop said motor and ignition means, a starting circuit and a stopping circuit to said thermostat, means in said controlling mechanism for connecting said two circuits alternately to said controlling mechanism to effect the starting thereof by closure of the connected circuit, a double-contact switcharranged to have but one contact closed, one contact being normally closed and connected in each circuit to the thermostat,and the other contact being arranged when closed to short the stopping circuit of the room thermostat, and means to operate said switch to short said circuit by an accumulation of unconsumed oil.

4. An oil burner for delivering fuel to a combustion space, having, in combination, means to supply combustion material to said space, a motor to operate said means, electrical means to ignite said material, a switch for said motor, a switch for said ignition means, a valve to control the supply of combustion material, a control motor,"a switch. for said control motor, a shunt circuit around said control motor switch, a two part control system for closing said shunt circuit to operate the control motor by operation of one of said parts, shift the control system for operation-by the other part after closure of the control motor switch, a plurality of cams rotated by said control motor, said cams operating the above named elements, comprising, the motor switch, ignition switch, valve, shifting means, and the control motor switch, the latter being opened to stop the control motor with the cams in one position when set in motion by one part of the control system and in another position when set in motion by the other part of the control system, said positions determiningthe idle and operative condition of the oil burner. v

5. An oil burner for a combustion space, having, in combination, means to supply fuel to said space, a motor to operate said means, a gas supply, electrical means to ignite the gas, a switch for said motor, a switch for said ignition means, a valve to control the supply of fuel a valve to release the gas, a control motor, a switch for said control motor, a shunt circuit around said control motor switch, a two part control system for closing said shunt circuit to operate the control motor shifting means to said motor, an

ignition means therefor,

'burner fuel, a valve for the ignition fuel, a

by operation of one of said parts, shifting means to shift the control system for operation by the other part after closure of the control motor switch, a plurality of cams rotated by said control motor, said cams operating the above named elements, comprising, the motor switch, ignition switch, fuel valve, shifting means, gas valve, and the control motor switch, the latter being opened to stop thecontrol motor with the cams in one position when set in motion by one part of the control system and in-another position when set in motion by the other part of the control system, said positions determining the idle and operative condition of the oil burner.

6. A fuel burner comprising, in combination, a fuel burner, means for supplying fuel, means for supplying air thereto, a motor for said two means, a switch for the motor, an ignition fuel supply, electrical ignition means therefor, a valve for the burner fuel, a valve for the ignition fuel, a switch for said ignition means, a plurality of cams mounted for simultaneous rotation, a control motor for rotating said cams, a switch for said control motor, a shunt circuit around said switch, means in said circuit to start the control motor each of said switches and valves being operated'by one of said cams, the control motor switch being closed at the beginning ofthe cam movement, and automatic means to break said shunt circuit when the control motor switch is closed, the revolution of said cams operating said Valves and switches to stop and start the burner and to stop the control motor.

7. A fuel burner comprising, in combina;

thereto, a motor for said means, a switch for ignition fuel supply,- electrical a valve for the switchfor said ignition means, a control mechanism, a control motor for operating said mechanism, a switch for said control motor, alternative starting means for said control motor,'said mechanism including means for operating the control-motor switch, shifting means for thealternative starting means, means to operate the ignition switch, means to operate said fuel valve, means to operate said ignition fuel valve, said last five means operating-after the operation of the first starting means, whereby combustion is established, the first of said five means being then operable to stop the mechanism, the other starting means being then operable to startthe mechanism to operate said oilvalve and the motor switch whereby to stop the burner, to shift the starting meanscand to open the control motor switch to stopstlie mechanism. c I

8. An oil burner apparatus having, in combination, with a heater having a furnace door, a bowl located in the. heater, a conduit for ios supplying air to the bowl, a fuel nozzle se cured to the furnace door arranged to direct fuel down into the bowl, an ignition means arranged in the door to project a flame in the path of said -flexible connections for said fuel and for said ignition means to permit the door to be opened, means to supply the fuel, means to, supply air through the con duit, and controlling means to start and stop the burner according to heat requirements.

9. An oil burhingapparatus having, in combination with a heater having a furnace door, a bowl in the heater, a conduit for supplying air to the bottom of the bowl, a fuel nozzle secured to the furnace door arranged to direct fuel into the bowl, an ignition means arranged in the door to project a gas flame in the path of said fuel,'means to operate the ignition means, means to supply the fuel, means to supply air through the conduit, said conduit being arranged to drain oil from the bowl, controlling means to start and stop the burner according. to heat requirements, said means including repeating means operable on failure of ignition to restart the controlling means, and means adapted to receive oil from the conduit on continued failure of combustion to render said burner idle and the controlling means inoperative.

10. An automatic safety device for an oil burner comprising, in combination, a burner,

fuel supplying means therefor, ignition means therefor, means for automatically starting and stopping .said burner, including operation of said ignition means, an electric control system for said automatic means, a repeating device in said system adapted to repeat the starting operation in case of failure of combustion, a device to collect unconsumed oil, a two-point switch in said system associated with said device, said device on accumulation of a predetermined quantity of oil being adapted to operate said switch, one side of said switch being arranged to open the circuit of the electric control and the other side of said switch being arranged to close a two wire one circuit repeating switch, each of said three-wire two-circuit switches having therein a wire common to both thermostat circuits, the common wire of the thermostat leading to one side of the heater control switch, the common wire of the heater control switch leading to one side of the cut out switch, the

common wire of the cut out switch and each side wire of the thermostat being the three wires leading to the apparatus, the other side of the heater control switch and the other side of the cut-out switch and one side of the repeating switch being connected to the heat side of the thermostat, and the other side of the repeating switch being connected to. the common wire of the cut-out switch for operation substantially as described, said out out switch and said control switch having at all times one circuit closed.

12. A thermostatic controlling devicehavheat and cold, a circuit thereto closed by a predetermined degree of heat, another circuit thereto closed by a predetermined lower degree of heat, heat supplying means associated with the second circuit, said means being arranged to' be started by closure of the second circuitnthe closu-re of thefirst circuit stopping the heat supplying means, means arranged to make said circuits efiective alternately' in succession on said heat supplying means, and a switch across said first circuit open only during the period of heat supply, said switch otherwise closing said first circuit to stop the heat supplying means on failure thereof to supply heat j r 13. In combination, an electrically operated burner, a control device to start and stop the burner in accordance with a demand for heat, one stopping and onestarting operation constituting a cycle for said control device, means to actuate said control device whereby to'stop and start the burner, a recycling switch arranged to be operated during the operating period of the burner by a failure of the power sufficient to extinguish the flame, said switch being further arranged so that, after operation by extinguishment of the flame and on return of power to the line, the switch actuates the control device to stop op eration of the burner and to reposition the same for the starting operation by said actuating means, whereby the control device on failure of the power passes through a complete cycle.

14. In an oil burner, in combination, a main motor, a control motor, means including a room thermostat for initiating operation of the control motor, a plurality of cams rotated by the control motor, an oil supply valve arranged to be operated by one of said cams, a gas supply valve arranged to, be operated by another of said cams, a switch controlling the control motor and arrangedto be operated by another of said cams, and a switch controlling the main motor and are ranged to be operated by another of said cams, the order of operations of the cams to start the oil burner being as follows: the closing of the control motor switch, the opening of the oil supply valve, the opening of the gas supply valve and the closing of the main mg, in combination, a device responsive to motor switch, the closin of the gas supply valve and the opening the control motor switch.

15; A fuel burner comprising, in combination, a burner, a fuel supply valve, a motor for said burner, ignition means for said burner, a

power operated controlling mechanism therefor embodying a rotating structure arranged to be moved intermittently and adapted during each revolution thereof to start and stop said burner and independently operable devices actuatd by said structure to control said motor, said fuel supply valve and said ignition means each independently of the 1 other and all in operative sequence to start the burner, and electrical means to actuate said mechanism comprising a motor'forrotating said structure and automatic control mechanism operable to effect actuation of said structure between two predetermined positions corresponding to the idle and operative conditions of the burner.

In testimony whereof, I have hereunto affixed m si atnre.

G S AF DAVID SUNDSTRAND. 

